Navigation integrated systems based on low-cost inertial sensors (typically MEMS based) often use magnetometer aiding to estimate heading during non-accelerated flight phases. Since assuring the reliability of magnetic aiding is a challenging task, however, contemporary systems use the magnetometer measurements only when the aiding is necessary and only for heading, not pitch and roll. In order to assure that the magnetometer measurements are not used for pitch and roll, contemporary systems typically do not use three-dimensional magnetic vectors in the aiding.